Mirror Man is an anime-only character that appears in Night 17 of Volume 1 and no other nights from that onwards, though he does make a final appearance at the end of Volume 3, which reveals his reflective mirror to be the destination of the train Gregory has boarded. His room is most likely somewhere near the catacombs of Gregory House, due to the nights after his appearance, Guest 1 is under the hotel. His room is also decorated with other mirrors, a table centerpiece, and a singular chair.
As his appearances have been brief, and the latter of the 2 being without dialogue, little can be inferred about his personality aside from the fact that he is rather enigmatic and among the more mysterious, aloof residents of the hotel. He may represent the first Guest's fear of self reflection, or his desire to run away from his problems, as all that is seen of him belying his mirror is that of a monstrous, intimidating eyeball not immediately connected to skin or a body.